Light and Its Uses. Reflection of Light specular (regular) reflection –all light rays that hit a...

Light and Its Uses

Reflection of Light• specular (regular) reflection– all light rays that hit a smooth surface are

reflected at the same angle

• diffuse reflection– reflected light is scattered in many directions

due to a rough surface

Mirrors

• Plane (flat) mirrors

– flat surface

– left and right are reversed

– give a virtual image

• the image you see is where you think the light came from, not where it actually came from

• concave mirrors

–mirror curves inward

– help to concentrate light on a spot called the focal point

• convex mirrors– mirror surface curves outward– the focal point is behind the mirror– used in automobile rear-view mirrors– objects appear farther than they really are

concave mirror

convex mirror

Color• the color of an object is determined what

color(s) of light are reflected– example: a red object looks red because red

light is reflected

Refraction of Light

• white light is made up of all the visible colors (ROYGBIV)

• each color (wavelength) of light is refracted (bent) a different amount– prisms can separate white light into its colors

(called dispersion)– red, with the longest wavelength, bends the

least– violet, with the shortest wavelength, bends the

most

• may make objects appear to be in different positions

A Rainbow

Lenses• transparent material that bends light to

create an image– converging lens• magnifying glass

– diverging lens• viewfinders in cameras

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